Film cassette with non-protruding film leader

Abstract

In a film cassette, a spool is supported for rotation in an unwinding direction inside a cassette shell, a filmstrip is coiled about the spool to form a roll with an outermost film convolution that is a nonprotruding leader, and a stripper is located substantially adjacent a passageway to the exterior of the shell for receipt between a leading edge of the leader and a next-inward film convolution of the roll to divert the leading edge into the passageway when the spool is rotated in the unwinding direction. According to the invention, the leading edge of the leader is inclined at one angle rearwardly from its center point on a longitudinal centerline of the filmstrip towards one longitudinal edge of the filmstrip relatively remote from the stripper and is inclined at another angle forwardly from the centerpoint towards another longitudinal edge of the filmstrip relatively close to the stripper. This arrangement facilitates advancement of the leading edge into and through the passageway.

I claim: 
     
       1. A film cassette comprising a spool supported for rotation in an unwinding direction inside a cassette shell, a filmstrip coiled about said spool to form a roll with an outermost film convolution that is a nonprotruding leader, and a stripper located substantially adjacent a passageway to the exterior of said shell for receipt between a leading edge of said leader and a next-inward film convolution of said roll to divert said leading edge into said passageway when said spool is rotated in the unwinding direction, is characterized in that: said leading edge of the leader is inclined at one angle rearwardly from its center point on a longitudinal centerline of said filmstrip towards one longitudinal edge of the filmstrip relatively remove from said stripper and is inclined at another angle, different than the first mentioned angle, forwardly from said centerpoint towards another longitudinal edge of the filmstrip relatively close to the stripper to facilitate movement of the leading edge into said passageway.   
     
     
       2. A film cassette as recited in claim 1, wherein said leading edge is inclined from said centerpoint towards said longitudinal edge relatively remote from said stripper at an angle that is greater than the angle at which the leading edge is inclined from the centerpoint towards said longitudinal edge relatively close to the stripper. 
     
     
       3. A film cassette as recited in claim 1, wherein said leading edge is inclined from said centerpoint towards said longitudinal edge relatively remote from said stripper at an angle that is at least twice as great as the angle at which the leading edge is inclined from the centerpoint towards said longitudinal edge relatively close to the stripper. 
     
     
       4. A film cassette as recited in claim 3, wherein the angle at which said leading edge is inclined from said centerpoint towards said longitudinal edge relatively remote from said stripper is substantially 15 degrees and the angle at which the leading edge is inclined from the centerpoint towards said longitudinal edge relatively close to the stripper is substantially 7 degrees.